1. Field of the Invention
The present invention relates to a display control apparatus and a display control method, and more particularly, to a display control apparatus and a display control method suitable for use in a video display apparatus that automatically performs image quality adjustment.
2. Description of the Related Art
Recently, image quality adjustment functions for higher image qualities, such as a noise reduction function, a gamma correction function, and a color tone correction function, have been mounted for many video display apparatuses such as TV receivers. In order to adjust individual parameters appropriately for these functions, a relatively sophisticated understanding of image characteristics is required. Therefore, it is common to preset, at shipping, some sets of parameters in accordance with the genre of video content or the like. The user can obtain videos with image qualities in accordance with purposes of watching, by a simple operation of selecting a set of preset parameters.
As one of such sets of parameters, there is a dynamic mode. In the dynamic mode, each parameter is adaptively varied in response to the characteristics of a video being displayed. As one example, when a video has high brightness over the entire screen, it is conceivable to set parameters so as to reduce the brightness and decrease the gamma correction value. Alternatively, when a video is dark with low brightness over the entire screen, it is conceivable to set parameters so as to increase the gamma correction value and enhance the contrast, and further to increase the color saturation. Adaptively carrying out such parameter control depending on video display allows the user to watch even videos which vary significantly in brightness or color shade temporally, always at easily viewable image quality.
Recent TV receivers primarily include models including an external input terminal for inputting moving image data or still image data. Some of such models allow a video of moving image data or still image data output from an external device connected to the external input terminal and a television broadcast video image to be displayed simultaneously. For example, video images composed of moving image data or still image data supplied from the external input terminal are arranged and synthesized at predetermined positions with respect to a television broadcast video image and displayed on a single screen.
Further, mounting an application that carries out editing of video and images in the TV receiver has also been proposed. In this case, moving image or still image data output from an external device and supplied via the external input terminal is supplied to the editing application and displayed. Using the user interface of the editing application, a user can perform such editing operations as image quality adjustment and the like on the video images displayed by the editing application. Results of the editing operations are continuously reflected in the display of images provided by the editing application.
In Japanese Patent Laid-Open No. 09-139865, a technique is described in which, for an image signal in which a plurality of video images are synthesized, the gamma correction value is selected so as to be synchronized with the display intervals of each of the video images based on range information for each video image displayed on the screen. According to Japanese Patent Laid-Open No. 09-139865, proper gamma correction can be carried out for each of the video images displayed on the screen.
Now, consider a case of using the dynamic mode and the editing application described above in combination. For example, the editing application displays on the screen a video image of the results of carrying out image quality adjustment on moving image data or still image data. The user can carry out further image quality adjustment on such moving image data or still image data with the editing application while looking at this display.
However, there is a problem in that, if the dynamic mode is selected as an image quality adjustment function of the TV receiver, image quality adjustment by the dynamic mode will be further carried out on the display of the results of image quality adjustment by the image editing application. As a result, there is a risk that the display will be one that does not properly reflect the intentions of the user as expressed in the image quality adjustment by the image editing application.
For example, for moving image data or still image data, there are cases in which data showing image sensing conditions at time of image sensing is added to such moving image data and still image data. Based on this image sensing condition data, the user can then carry out image quality adjustment that takes into account the environment at the time of image sensing using the image editing application. However, it is not always the case that image quality adjustment by the dynamic mode reflects the environment at the time of image sensing, and there is a risk that the intentions of the person doing the image sensing at the time of image sensing may not be properly reflected.
In addition, with the method of Japanese Patent Laid-Open No. 09-139865, because it attempts to perform correction of each range of each of the video images displayed in the screen, for example, it is possible to control matters so that image quality adjustment is not performed only on the range of a video image displayed by an image editing application for which image quality adjustment is unnecessary. However, in this case, it is necessary to enable/disable the image quality adjustment function for each pixel, which complicates circuit configuration.